The proposed research will continue a series of experiments on the discrimination of word-length auditory patterns. The work accomplished to date has established certain major differences between human listeners abilities to resolve the spectral, temporal, and intensive dimensions of the components of auditory patterns (tonal sequences) and their abilities to resolve the same components in isolation. These differences reflect properties of auditory perception not predictable from previous psychoacoustic studies of the discriminability of simpler auditory stimuli (single tones, noise bursts, clicks) nor from temporal masking patterns. The primary new finding is that of a very strong tendency to distribute auditory attention systematically, but non-uniformly over the spectral and temporal range of auditory patterns when testing procedures force the listener to attempt to resolve the total information available within a pattern. The other, related, major finding is that the individual components of patterns can be resolved essentially as accurately as when they are presented in isolation, when the testing procedure permits the listeners to focus on a specific component. The experiments on which these generalizations are based will be extended to determine the spectral and temporal range of selective auditory attention, whether it can be multi-dimensional, the course of auditory perceptual, the general role of stimulus uncertainty in auditory pattern perception, and the manner in which gross properties of auditory patterns serve as cues to selectively attend to specific pattern components. The scope of these studies will also be increased to include the determination of individual differences in auditory pattern discrimination ability among normal and impaired listeners, and to the creation of a standardized test of these capabilities. Auditory patterns consisting of sequences of sounds synthesized to incorporate the resonant and source characteristics of the human vocal tract will also be investigated.